I'm a student studying EM right now and the concept of wave impedance has come up. I think I understand the mathematical derivation of it and I understand how to use it to calculate reflection and transmission coefficients. However the unit Ohm I think is confusing me.
In standard electrical circuits the electrical impedance is related to the power dissipated. There is a voltage drop across and a current through the impedance. In purely capacitive or inductive loads there is simply a phase shift (in AC). This stuff is mostly intuitive to me as I can kind of imagine 'electrical energy' moving through a circuit and how it interacts with these components.
Wave impedance seems to me, to be a measure of an intrinsic material property, there is no power dissipated. In my limited time with this topic it seems to me that it doesn't have much real/physical meaning except at the boundaries of materials. This is doing my head in, the same unit seems to be being used for two seemingly unrelated things, more than that, the same word 'impedance' is being used.
Is there some relation between electrical and wave impedances that I've misunderstood? Is there a more intuitive way to wrap my head around wave impedances (some analogy maybe)?
Or will I need to come to terms with $\eta$ being a useful number derived from Maxwell's equations that simply exists.